On some EHCI debug controllers after the host controller driver isactivated, the debug controller will occasionally fail to submit abulk write URB. On controllers that exhibit this behavior a dummybulk write must get submitted to resynchronize the device.

The "dummy bulk write" does not get received by the host attached tothe other end of the usb debug device. The usb debug device simplyacknowledges the "dummy bulk write" and returns to a usable state.

The behavior, without this patch is that you see missing text from acomplete kernel boot when using the keep option to the earlyprintkkernel argument.